[X86] When applying the shuffle-to-zero-extend transformation on floating point, bitcast to integer first.

Fix issue described in PR34577.

Differential Revision: https://reviews.llvm.org/D37803

llvm-svn: 313256

1 files changed, 9 insertions, 4 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index ee82c80625a..3089204ba8d 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -27153,13 +27153,18 @@ static bool matchUnaryVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
       }
       if (Match) {
         unsigned SrcSize = std::max(128u, NumDstElts * MaskEltSize);
-        SrcVT = MVT::getVectorVT(MaskVT.getScalarType(), SrcSize / MaskEltSize);
-        if (SrcVT != MaskVT)
+        MVT ScalarTy = MaskVT.isInteger() ? MaskVT.getScalarType() :
+                                            MVT::getIntegerVT(MaskEltSize);
+        SrcVT = MVT::getVectorVT(ScalarTy, SrcSize / MaskEltSize);
+
+        if (SrcVT.getSizeInBits() != MaskVT.getSizeInBits()) {
           V1 = extractSubVector(V1, 0, DAG, DL, SrcSize);
+          Shuffle = unsigned(X86ISD::VZEXT);
+        } else
+          Shuffle = unsigned(ISD::ZERO_EXTEND_VECTOR_INREG);
+
         DstVT = MVT::getIntegerVT(Scale * MaskEltSize);
         DstVT = MVT::getVectorVT(DstVT, NumDstElts);
-        Shuffle = SrcVT != MaskVT ? unsigned(X86ISD::VZEXT)
-                                  : unsigned(ISD::ZERO_EXTEND_VECTOR_INREG);
         return true;
       }
     }